INVESTIGATING EARTH's OCEANS Today some two centuries later the func tions of the original United States Coast Survey fall to the National Oceanic and Atmospheric Administration NOAA which conducts research on the oceans and the atmosphere Modern researchers con tinue to build upon the knowledge of the early ocean explorers by studying sea life and the seafloor as well as the physical character istics and chemical composition of seawater This research helps us get to know the oceans better which in turn helps us to better moni tor their health Scientific exploration in the past two cen turies has answered many questions about the sea One of the most impressive aspects of the oceans is their vastness We now know that 71 percent of the planet is covered with ocean and that accounts only for surface area To really get a sense of the size of the ocean it helps to consider the volume of the planet s biosphere The biosphere is all parts of Earth that can support life includ ing the land the oceans and part of the atmosphere Imagine that the volume of Earth's biosphere is contained in a 32 ounce 1 liter soda cup Of the biosphere in this cup almost 30 ounces 88 liter are ocean Given the immense size of the oceans it is
INTRODUCTION not surprising that they hold a lot of life Of the 33 animal phyla or categories of animals on Earth 30 consist of ocean dwellers If you re interested in learning more about the oceans and why they need to be protected this book is a great place to start As you read keep in mind that this is just a small sampling of what scientists have learned about the oceans so far And even though people have studied the oceans for centuries there will always be more to
CHAPT THE WoRLD OCEAN t has been called the new frontier The great body of water embracing Earth's continents is also known as the world ocean Its major subdivisions are the Pacific the Atlantic the Indian and the Arctic oceans Some people divide the world ocean into the North Pacific South Pacific North Atlantic South Atlantic Indian Arctic and Antarctic a total of seven The term seven seas however originated with medieval ARCTIC OCEAN NORTH AMERICA RIDGE A S NORTH AMERIC EUROPE KARAiLaurTAN TRENCH ATLANT TRENCH PACIFIC OCEAN 3 MID PACIFIC MTs AFRICA ATLANTIC OCEAN BASIN SOUTH MERICA BASN ANGOLA 2 BASIN MANHK PLATEAU EB MID AUSTRALIA TEST RIDGE SOUTHWEST PACIFIC ARGENTINE INDIAN RIDGE INDIAN OCEAN ATLANTIC INDIAN RIDGE KERGUELEN ENDERBY PLATE AT E PACIFIC ANT ARCTIC RIDGE 1994 Encyclopaedia Britannica Inc ANT ARCTICA 2500 km Cylindrical Equal Distance Projection Major features of the ocean basins IO
THE WORLD OCEAN Arabic geographers who knew only the waters of Europe and Asia Around the borders of the oceans lie par tially enclosed seas and gulfs such as the Mediterranean Caribbean Baltic Black Red and North seas the Gulf of Mexico and the Persian Gulf The landlocked Caspian Sea was part of a great ocean in an earlier geologic era Gulfs are generally described as extensions of oceans or seas The Gulf of Mexico is larger than most seas Straits are narrow passage ways connecting two large bodies of water such as the Strait of Gibraltar between the Atlantic Ocean the Mediterranean Sea and Oceans seas gulfs and straits cover about 71 percent of Earth's surface No other known planet is as watery as Earth The Atlantic Pacific Indian and Arctic Oceans cover 129 428 700 square miles 335 218 800 square kilometers The Pacific Ocean is the largest It occupies almost one third of Earth's total area The oceans are not evenly distributed over Earth s surface About 43 percent of their total area lies in the Northern Hemisphere and 57 percent in the Southern Hemisphere The word ocean is derived from Oceanus in Greek mythology one of the Titans He was a son of Uranus the sky and Gaea Earth II
